An significant characteristic of ecclesiology since the Second Vatican Council, especially since Lumen gentium and Unitatis redintegratio, is a shift in emphasis from what the Church is to what she is called to be. It is the move from a static to a dynamic understanding of the four marks of the Church. The Church is one, holy, catholic, and apostolic, but she is also the means to these ends. Her marks make manifest her mission to call the baptized to closer unity, deeper holiness, broader catholicity, and greater apostolicity. In other words, the development of doctrine from Boniface VIIIís Unam sanctam to John Paul IIís Ut unum sint is one of emphasis: the Church now seeks to highlight, share, and expand what she already possesses. Much like the kingdom of God itself, the Church is "already and not yet."

The Church is one. The Church is the embodiment of the intimate union that exists between Christ and those who corporately profess the Catholic faith: one Lord, one faith, one baptism (Eph 4:5). But the Church recognizes more than ever her duty to those who acknowledge the Lord and his baptism but have yet to profess the one faith. Because all those baptized in the Lord are members of the Church, even if imperfectly, and because many elements of sanctification and truth may be found outside the visible confines of the Church, the Churchís inherent unity compels her to ecumenism, to labor for the unity of all Christians.

The Church is holy. As the embodiment of the intimate union between Christ and the faithful, it is hers to lead each of her members to sanctity. The Church is the Bride of the Lamb (Rev 21:9). The Church is holy because of Christ. Yet she cannot but be mindful of the fact that in times past, present, and in the immediate future, many of her members fall short of their Christian responsibility: sanctity in the glory of God. However the holiness of the Lord, who sanctifies the Church, provides the impetus for the sanctification of each of her members.

The Church is catholic. As the embodiment of the intimate union between Christ and the faithful, it is hers to proclaim the gospel to all nations (Matt 28:19). Though one, the Church is also diverse because of her universal mission. Adopting and adapting as many languages and cultural expressions as are necessary for the proclamation of the gospel, the Church is open to one and all. Her catholicity is both a sign and instrument of her universal mission to propagate the faith.

The Church is apostolic. As the embodiment of the intimate union between Christ and his faithful, it is hers to manifest the unbroken Petrine ministry and apostolic witness as her foundation (Matt 16:18; Eph 2:20; Rev 21:14). From Peter and the apostles to John Paul II and the bishops, the Church bears an unbroken line of constancy, truth, and trust. With the inspiration of the Holy Spirit, the Holy Father and his bishops now lead the Church into the third millennium of Christianity as a beacon of light and hope for the whole of humanity.

Thus, ecclesiology from the Second Vatican Council to our own day has developed from a theological discipline that examines the status of the Church as she was and as she is to a studied projection of the Churchís hopes for her own unique future in the sanctification of the world. In more ways than one, the Council enlivened the people of God with a dynamism of self-understanding to be one, holy, catholic, and apostolic while enroute to a kingdom that is "already and not yet."